The early Romans didn’t much like the letter K. 
According to Tommy Thompson, writing in 1942 (The ABC of our Alphabet), 
the letter was disliked ‘from a standpoint of design’, so they, he writes ‘substituted C for the voiceless K’.
He may be right but when it comes to the alphabet there is one writer I turn to: David Diringer and his The Alphabet, A key to the History of Mankind (Hutchinson, 3rd edition, 1968). 
Now Diringer has this to say of K: ‘…the Greek alphabet had two other signs for the k-sound, the K and the Q, and we find in the South Etruscan alphabet the sign C used (as a k) only before e and i, the K used before a, and the Q only before u (Etruscan has, as we have seen, no o). The Latin alphabet adopted all the three letters with their phonetic values, but in time it dropped the K (which, however, continued to be used as the initial of well-known or official words, such as Kalendae or Kaeso) and used C for the sounds of both g and k, the letter Q being retained for the k when followed by a u.’ (The Alphabet, 1968, vol 1, p.419).
I trust that is helpful – and I’d appreciate any comments.
As for the modern K, well, there are many variations and most of them horrible. Particularly when in the Egyptian style!
My preference is for the style where the upright does not quite connect with the <
If you liked this you might like a diversion on R here.
One reply on “The Letter K”
What a fascinating little essay. This is a new world to me – I had no idea just how much is attached to a single letter. I was merely trying to find a date for letters appearing on an old crowbar when I came across this article. I did not find the answer to my question but this is far more interesting !